Anti-rust compositions



ANTI-RUST COMPOSITIONS Robert Tirtiaux, Notre-Dame de Gravenchon, andJean Baptiste Signouret, Pau, France, assignors to Esso Standard SocieteAnonyme Frangaise, Paris, France, a body corporate of France phenolformaldehyde copolymers and to the use of these copolymers in anti-rustcompositions.

Rust inhibiting agents are known which will retard rust formation of aniron surface. It is believed that rusting is catalysed by the existenceof centres of rust and that the rust inhibiting agent destroys theauto-catalytic effect of the rust by destroying the gel-like structureof the rust. Another and more obvious method of preventing corrosion ofan iron surface is to completely protect the surface, by means of animpermeable skin, from the elfects of the surrounding atmosphere.

It has been found difiicult to permanently protect a metal surface bymeans of oil unless fresh,applications of oil are periodically applied.Even with thick oils and oils which have been thickened by the additionof petrolatum, the oil film does not remain continuous, and rusting willoccur. It is believed that protection of an iron surface against rust bymeans of an oil film is not possible for two reasons. Firstly, the oilfilm breaks up and leaves active centres of the surface unprotected fromthe atmosphere; and secondly, that condensed water has a greateraifinity for the metal surface than the oil and in time the waterdisplaces the oil on the surface of the metal.

.The present investigation was undertaken in order to devise a copolymerwhich, when added to a lubricating oil, would give a composition thatwould form a lasting and impermeable film on the metal surface. Asuitable polymer as described hereafter, derived from phenol andformaldehyde was devised, and on further experimentation, it wasdiscovered that if alkaline metal naphthenates or sulphonates were addedto an oil solution of this copolymer, an eflicient rust inhibitingcomposition was obtained. This discovery was unexpected since thecomposition Was found to be far superior to either a compositionconsisting of lubricating oil and the copolymer, or a composition oflubricating oil and the alkaline metal naphthenates or sulphonates. Theeffectiveness of the composition of the present invention is dependenton the synergistic effect of the copolymer and the alkaline salts ofsulphonates or naphthonates when in an oil solution.

The rust inhibiting composition of the present invention comprises anoil, alkoxylated phenol formaldehyde copolymer and an oil-solublealkaline metal naphthenate h or sulphonate.

United States Patent F thenates or sulphonates may be dispersed in adrying oil, I Pigments such as which may be natural or synthetic. metaloxides may be included. It is desirable to include in the rustpreventing compositions bitumons or coal tar.

The copolymers of the present invention are prepared by copolymerisingformaldehyde, which may be in the iform of a formaldehyde polymer, withan alkoxylated phenol. The term alkoxylated phenol refers to the productobtained by reacting an alkylene oxide with a phenol. h

The preferred phenols are mono and di-alkyl derivatives of phenol inwhich the alkyl group or alkyl groups each contain from 6 to 20 carbonatoms and preferably from 6 to 12 carbon atoms. The alkyl phenols may beformed by alkylating a phenol with an olefin in the presence of aFried'el-Crafts catalyst; the alkyl phenols soobtained having branchchain alkyl groups. Suitable examples of alkyl phenols are n-octylphenol, iso-octyl phenol, ditertiary butyl phenol, isobutyl phenol, amylphenol and heptyl phenol. The alkyl groups are prefer-' ably situatedortho or para with respect to the phenolic group.

The alkylene oxide 'used to prepare the alkoxylated phenol may have from2 to 6 carbon atoms and prefer" The alkoxyl ably is ethylene oxide orpropylene oxide. ated phenol may be prepared by reacting the alkylene loxide, such as ethylene oxide, with a phenol in the presonce of asuitable inert solvent, such as hydrocarbon, in the presence ofcatalytic amounts of a Friedel-Crafts catalyst such as borontrifluoride. It is preferable to fix from 1 to 4 mols of the alkyleneoxide on 1 mol of the 1 alkyl phenol. Alternatively, the alkoxylatedalkyl phenol The oil that may be used in the compositionmay besynthetic, natural or mineral oil. For reasons of economy it ispreferable to use a mineral oil which may be a lubricating oil such as aspindle oil having a viscosity of to S.U.S. at 100 F., or a cylinderoil. An oil with a viscosity within the range 100 to 500 S.U.S. at 100F. may be used. In order to increase the viscosity of the compositionpetrolatum may be added until a consistency similar to that of vaselineis obtained.

When it is desired to use the composition in rust preventing paints, thecopolymer and alkaline metal naph may be prepared by condensing apolyal-kylene glycol, preferably containing from 1 to 4 glycol residues,with the alkyl phenol.

The alkoxylated phenol may be copolymerised with the formaldehyde in thepresence of an alkaline or Friedel- Crafts catalyst. Ammonia and sodiumhydroxide and potassium hydroxide are suitable alkylene catalysts, and.

boron trifluoride in the form of boron trifluoride/ether complex, is aparticularly preferred Friedel-Crafts catalyst. The copolymerisation maybe affected by heating a mixture of the alkoxylated alkyl phenol,preferably ethoxylated phenol, and formaldehyde at a temperature of toC. for a period for 5 to 7 hours and preferably for a' period of about 6hours.

Ammonia may be included in the copolymer by copolymerising formaldehyde,ammonia and the alkoxylated phenol. The copolymerisation may be carriedout by heating formaldehyde, ammonia and alkoxylated alkyl; phenol at atemperature of 150 to 160 C. for 5 to 7 hours, preferably for a time ofabout 6 hours. The best method of copolymerising with ammonia is toinject am: monia into a mixture of the alkoxylated alkyl phenol andformaldehyde at a low temperature, for example 50 to 60. C., for aperiod of 5 to 6 hours, stopping the addition of ammonia andthen heatingthe reactants to a higher temperature of the order of 100 to 160 C. andprefer: ably to 100 to 110 C., and maintaining the heating at thehigher'temperature for a period of 5 to 7 hours.

The product of the-- polymerisation process may be .freed of volatilematerials by stripping in vacuo and dispolymer.

solved in mineral oil to give a concentrate of the co- A suitablecopolymer concentrate contains about 50 wt. percent of the copolymer.

The preparationv of resin A and resin B serves as an illustration of theprocess used to prepare the copolymers.

2,978,423 Patented Apr. 4, 19 61 reacted at 120 to 130 C. using 0.5% ofboron trifluoride/ether complex as catalyst, and the alkoxylated octylphenol (100 g.), so obtained was copolymerrsed with trioxymethylene (15g.) using 0.5 g. boron tritluoride/ether complex as catalyst, at atemperature between 110 and 120 C. for 6 hours. The product was thendispersed in a mineral oil (100 g.) of viscosity index 140 and viscosityat 37.8 C. of 32.1 centistokes. Filtration at 120 C. gave a 50% solutionof resin A.

EXAMPLE 2 Preparation of resin B The ethoxylated octyl phenol, preparedas in Example 1 (100 g.), was copolymerised with trioxymethylene (15 g.)using boron trifluoride/ether complex as a catalyst, at 60 to 65 C. for5 hours. During this stage of the process ammonia was continuouslyinjected into the monomer mixture. Injection of the ammonia was thenstopped and the heating was continued for a further 2 hours at 150 C.,and the product so obtained was dispersed in spindle oil (100 g.).Filtration at 120 C. afforded 50% concentrate of resin B.

The properties of compositions according to the present inventioncontaining resin A and resin B are shown in Tables I and II. Theconcentrates may be conveniently diluted to prepare the desiredcompositions which may contain from 0.1 to by weight of the copolymer,and preferably from 0.5 to 5% by weight of the copolymer.

The sulphonates are alkaline metal sulphonates, sodium being thepreferred alkaline metal. The sulphonates may be oil-soluble petroleumsulphonates such as the mahogany acids. The sulphonates may be a mixtureof sulphonates containing from 12 to 25 carbon atoms and preferably from14 to 18 carbon atoms or a molecular weight of 400 to 600. It ispreferred that the composition of the present invention contains from0.5 to 5% by weight of alkaline metal sulphonates.

Oil-soluble alkaline metal naphthenates may be used in place of thesulphonates. Sodium naphthenates are preferred having from 8 to 18carbon atoms per molecule.

It has also been discovered that the composition may be particularlyimproved by the addition of animal fatty oils or wool fats such assuintine, lanolin, degras. The advantages derived from the addition ofsuintine, which may be added to the order of 10 wt. percent are clearlydemonstrated in Table I. It is also desirable to include in thecomposition polyvalent metal salts of sulphenated fatty acids,naphthenic acids, or phenols. Examples of suitable polyvalent metals foruse in salts are lead, copper, iron, tin, zinc and manganese. Theinclusion of lead naphthenates and/or zinc naphthenate of the order of 2/2 wt. percent is advantageous.

It is also desirable to include in the composition up to 10% ofpolyalcohols of natural animal or vegetable origin such as suintine,degras, lanolin, spermacetic oil, beeswax and Chinese wax.

The synergism exhibited by the composition of the present invention isdemonstrated by Table I and Table II.

TABLE I 10 subjected to these conditons to show the first signs of rust,measures the resistance time of the anti-rust composition in questionand therefore, its eflicacy.

TABLE II Compgsition; Humidification test. time in hours A. 5 wt.percent lanolin 10 wt. percent sodium sulphonates 1 710 35 wt. percentnaphthenic oil 100 SUS at 100 F. 20 B. 98.4 wt. percent composition Aplus 1.6 wt.

percent resin A 790 C. 98.4 wt. percent composition A plus 1.6 wt.

percent resin B 800 D. 10 wt. percent lanolin 10 wt. percent sodiumsulphonates 1 460 80 wt. percent white spirit E. 98.4 wt. percentcomposition D plus 1.6 wt.

percent resin A 500 F. 98.4 wt. percent composition D plus 1.6 wt.percent resin B -2 500 1 The sodium sulphonates were sodium petroleumsulphonates with a molecular weight of 440460.

The humidification test referred to in Table II. was

measured in a humidity cabinet fitted with an air line delivering afixed rate of air, a water heater and a thermostat to maintain atemperature of 100 F., and an air line delivering air through diffusiondiscs at a specified rate. The test panels are of mild steel which issand-blasted to a uniform rust-free surface and then 1. A rustinhibiting composition consisting essentially of oil, about 0.1 to 10.0wt. percent of a polymeric material consisting of an alkoxylated alkylphenolformaldchyde copolymer and about 0.05 to 5.0 wt. percent of an oilsoluble material selected from the group consisting of alkali metalsulfonates of 12 to 25 carbon atoms and alkali metal naphthenates of 8to 18 carbon atoms, and

' wherein said alkoxylated alkyl phenols contains about one to four C toC alkylene oxy groups per molecule and about one to two C to C alkylgroups per molecule.

2. A rust inhibiting composition consisting essentially of a majorproportion of mineral oil, about 0.1 to 10.0 wt. percent of a polymericmaterial prepared by copolymerizing a group of reactants consisting offormaldehyde, ammonia and an alkoxylated alkyl phenol, and about 0.5 to5.0 wt. percent of an oil soluble material selected from the groupconsisting of alkali metal sulfonates of Anti-rust compositionsPercentages by weight Formula VII VIII IX X XI XII Oil of viscosity at37.8 C.,

32.1 centistokes 95.8 94.2 94.2 95

Oil of viscosity at 37.8 C.,

centistokes Resin A (50% solution) Resin B (50% solution) Nn. sulphonateof molecular weight about 500(50%soln.)- 4.2 4. 2 4.2 4.2 SuintineHumidification test, Time in a hours 20 520 490 12 12 15 5 12 to 25carbon atoms and alkali metal naphthenatcs of 8 to 18 carbon atms,'andwherein said alkoxylated alkyl phenol contains about one to four C to Calkylene oxy groups per molecule and about one to two C to C alkylgroups per molecule.

3. A rust inhibiting composition consisting essentially of a majorproportion of mineral oil, about 0.5 to 5.0 wt. percent of a polymericmaterial consisting of an ethoxylated alkyl phenolformaldehydecopolymer, about 0.05 to 5.0 wt. percent of an oil soluble sodiumsulfonate of 12 to 25 carbon atoms, and up to 10 wt. percent of amaterial selected from the group consisting of suintine and lanolin,wherein said ethoxylated alkyl phenol contains one to two C to C alkylgroups per molecule.

4. A method of preventing rusting of iron surfaces which comprisescoating said surface with a film of a rust inhibiting compositioncomprising a major proportion of mineral oil, 0.1 to 10.0 wt. percent ofan alkoxylated alkyl phenol-formaldehyde copolymer, and about 0.05 to .0wt. percent of an oil soluble material selected from the groupconsisting of alkali metal sulphonates of 12 to 25 carbon atoms andalkali metal naphthenates of 8 to 18 carbon atoms, wherein saidalkoxylated alkyl phenol contains about one to four 0, to C alkylene oxygroups per molecule and about one to two C to C alkyl groups permolecule. I

I 5. A method of preventing rusting of iron surface which comprisescoating said surface with a film of a rust inhibiting compositioncomprising a major amount of mineral oil, 0.5 to 5.0 wt. percent of anethoxylated alkyl phenol-formaldehyde copolymer, and about 0.05 to 5.0wt. percent of an oil soluble sodium sulphonate of 12 to 25 carbon atomsand wherein said ethoxylated alkyl phenol contains about one to fourethylene oxy groups per molecule and about one to two C to C alkylgroups per molecule.

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Baker et al.: Polar-Type Rust Inhibitors, pages 2338- 2347,Industrial and Engineering Chemistry, volumn 40, No. 12 (December 1948).

1. A RUST INHIBITING COMPOSITION CONSISTING ESSENTIALLY OF OIL, ABOUT0.1 TO 10.0 WT. PERCENT OF A POLYMERIC MATERIAL CONSISTING OF ANALKOXYLATED ALKYL PHENOLFORMALDEHYDE COPOLYMER AND ABOUT 0.05 TO 5.0 WT.PERCENT OF AN OIL SOLUBLE MATERIAL SELECTED FROM THE GROUP CONSISTING OFALKALI METAL SULFONATES OF 12 TO 25 CARBON ATOMS AND ALKALI METALNAPHTHENATES OF 8 TO 18 CARBON ATOMS, AND WHEREIN SAID ALKOXYLATED ALKYLPHENOLS CONTAINS ABOUT ONE TO FOUR C2 TO C6 ALKYLENE OXY GROUPS PERMOLECULE AND ABOUT ONE TO TWO C6 TO C20 ALKYL GROUPS PER MOLECULE.